There used to be another publication called "Daytime Serials" that had monthly synopses of most of the soaps as early as 1973 (and possibly a year or two earlier). One woman published it. I've hoped some of those would turn up on eBay but I haven't had any luck so far.

Those are the ones that FrenchFan provided. The stuff from 1972-1975. I've put in a request, and FrenchFan is checking soon to see if there are some more issues from 1974-1975 that can be provided.